A week after Nintendo's Wii debuted in November, the Wall Street Journal reported that the gaming console was leaving some users as sore as the gym often does. Unlike traditional hand-held video games, where users sit on the couch exercising little more than their thumbs, the Wii (pronounced "we" not "why") features digital sensors that let users virtually play the game. In Wii Sports, a game that comes with the console, users mimic the motions used in sports like bowling, tennis and baseball. In other words, the game may be virtual, but the physical exertion is very real.

So much so that, according to the Journal, gamers complained of "aching backs, sore
shoulders  even something some have dubbed "Wii elbow." Nintendo
spokeswoman Perrin Kaplan downplayed the report, saying the company hadn't
received any complaints from users about soreness. "If people are finding themselves sore,
they may need to exercise more," she said. "It was not meant to be a
Jenny Craig supplement."

But that's where she may be wrong. Not only have some gamers started turning the
Wii and other similar active gaming consoles into a new form of exercise, but medical researchers are touting their health potential for more than just weight loss. A research team at the University of Toronto is developing a "therapeutic video game" to treat children who suffer from hemiplegic cerebral palsy, a condition that can partially paralyze one side of the body. If the children regularly use their weaker side, their motor function can improve. The problem is getting the children to do so outside of therapy sessions. Active video games might do the trick, thought William Li, an undergraduate engineering student at the University of Toronto who is conducting research at the university's Bloorview Kids Rehab teaching hospital.

With university researchers, he devised a game console that requires the children to use
their dominant hand to hold down a button on their chair. With the weaker
hand, the children can play an active video game. "It's a lot of fun to use,
and the movements are the types of things that might be promoted in physical
therapy or occupational therapy," Li says. "[And] the kids don't
have to feel different. This is a game they can take home and play with
siblings and friends."

Wii's psychological impact may even speed up the recovery process. Mary Jane
Zamora, who lives in Redondo
Beach, Calif., has battled breast cancer since she was diagnosed in February
2005. After a round of chemotherapy before Christmas in December, she was
too tired to get off the couch. Then her grown daughters brought over a
Wii. Together they played bowling, tennis and golf. "It got a little
exhausting," Zamora says, but she was hooked and began playing on her own
every day. Soon after joining a local bowling league, she was named the league's Most Improved Player. "What this game did
for me was encourage me that I could still do these kinds of things," she
says. "It came around when I needed it. I can see where people could really
benefit from being able to interact without having do to much physical
exertion."

But weight loss is still probably the biggest health benefit the Wii will have for users. Active video games like the Wii can fight child obesity, according to a report published by the Mayo Clinic in the January issue of
Pediatrics. In that study, researchers found that children burned
three times as many calories playing "active" video games
versus playing traditional hand-held video games. Because the study was done
before the Wii debuted, researchers tested Sony's EyeToy and Microsoft's
Xbox. But Lorraine Lanningham-Foster, the report's lead researcher, expects
the Wii to have the same effect. "If children are up moving around versus
sitting down, then they're going to burn more calories," she says.

In December Mickey DeLorenzo, a computer programmer in Philadelphia, hypothesized that he could lose weight by playing the Wii for 30 minutes a day. He lost
nine pounds in six weeks and is on his way to becoming the next Jared of
Subway fame. In January DeLorenzo signed a book deal, tentatively titled
The Wii Workout and teamed up with Traineo.com, a social networking site for dieters
and fitness buffs, to feature his new regime. "It's becoming something like
a Richard Simmons show," says DeLorenzo, who's received dozens of fan
emails. "People will write, 'You've inspired me to buy a Wii and start
working out.'"

Two months after dismissing the Wii's exercising potential, Nintendo
spokeswoman Perrin Kaplan now embraces it. "One of our hopes was that people
would find a way to enjoy the Wii sitting on the couch or getting up and
moving their body around," she says. "This huge fitness craze was more than
we had anticipated."